It is well-known to use rotating drums in photographic processing apparatus. US-A-4 613 223 discloses an arrangement in which a flexible sheet of photographic material is driven along an endless curved path within a processing tank by passing the sheet through nips formed between at least one pair of driven rollers. At least one of the driven rollers is the drum itself. During processing, the emulsion (sensitive) surface of the sheet is arranged not to come into contact with any stationary part of the processing vessel as it is being processed. This prevents damage to the surface during processing. After driving the sheet around the endless path for a predetermined number of cycles, which defines the processing time, the sheet is then directed out of the processing tank.
The arrangement described above, has the disadvantage that little or no agitation is applied to the emulsion surface of the photographic material being processed. This may result in uneven processing of the material and variable sensitometry.
Furthermore, relatively large volumes of processing solution are required which makes the arrangement disclosed unsuitable for unstable processing chemistry and single use chemistry as large volumes of processing solutions need to be discarded on a regular basis.
U.S. Pat. No. 2 605 684 discloses an arrangement in which helically wound grooves formed on rollers are used to transfer processing solution from a reservoir and to apply the solution to photographic material being processed. A small portion of the surface of each grooved roller is used to effect such transfer and application.